Refractory element for stoves and the like



April 18,1950 J. c. MILES 2,504,141

REFRACTORY ELEMENT FOR STOVES AND THELIKE Filed April 8, 1946 I 2 Sheets-Siiet 1 L9 I f I E A 1:. I g F e? 6/ /6 k t 30 f1 \KLL E /Z I Z6 1 I 7 Z v .7770? 071 I GJfi/ea 5. 1 9

April 18, 1950 Filed April 8, 1946 J. c. MILES 2,504,141 REFRACTORY ELEMENT FOR STOVES AND THE LIKE 2 Sheets-Sheet 2 L2 6 2: t I I ,ffiaezzzaz" /5%7Z ZZ j Patented Apr. 18, 1950 REFRACTORY ELEMENT FOR STOVE S AND THE LIKE J olm 0. Miles, ilrbana, Ill., assignor to The Board of Trustees, the University of lllinois Application April 8, 1946, Serial No. 660,495

This invention relates to a hot water heater or the like.

The hot water heater which is the subject of this invention is especially designed for supplying hot water in installations where relatively small amounts of water are required. It is of very simple construction, and is quite cheap to build. The apparatus has all heated parts water-jacketed, o that it may be made of metal. Although preferably used as a water heater, the structure may also be used as a boiler.

Previous water heaters using coal the power have been bulky, expensive, and required insulation with firebrick or the like to protect the sides from the heat of the fire. The present construetion is much superior to these previous water heat-- ers in that it islight in weight, inexpensive to construct, and is highly efficient in furnishing a constant supply of hot water.

The invention will be described as related to the accompanying drawings, which illustrate one embodiment of the hot water heater. f the drawings, Fig. l is a vertical sectional elevation taken substantially through the center of the heater; Fig. 2 is a section taken along line 2-2 of Fig. 1; Fig. 3 is a sectiontaken along line 3-3 of Fig. 1; and Fig. 4 is a perspective view of one section of the secondary air intake thimble.

The hot water heater shown in the accompanying drawings comprises firebox it of substantial- 1y circular cross-section containing a coking zone I l, a coke-burning zone 12, and a combustion zone l3. Communicating with the combustion zone is passageway l4 serving as an outlet for the gases of combustion. This passageway is connected at the top with a stack I5. The firebox It and passageway M are made of metal, and are water- J'acketed b means of partitions I6 and I1. The water jacket l8 around the firebox is connected to water jacket l9 around the combustion gas passageway, as with a short U-shaped pipe 20. Water is permitted to flow into the firebox jacket I8 through said pipe 2|, located near the bottom of the heater and up around the firebox and the passageway I4, and out the exit pipe 22. In this travel the water is heated by the fire in the firebox, and the heated gases of combustion in the passageway M.

The bottom of the hot water heater contains an ash pit 23, separated from the firebox by an inclined fixed grate 24 and a flat shaker grate 25. The ash pit has an ash removal door 26, in which is located a small air hole 21.

At the top of the firebox there is located a refractory thimble 28, of triangular cross-section,

1 Claim. (01. 126-146) having one side curved to fit against the side of the firebox. The thimble has a hollow interior 29, which forms a part of the combustion zoneof the heater. The thimble 28als0 has a channeled exterior 3E communicating with the atmosphere through a hole in the side of the firebox. This air hole is formed by means of a short pipe 31 passin through the water jacket. The channel 36 in the refractory thi'mble is closed at its curved side by the metal wall or the water heater, and is partially closed at its other two sides by means of refractory elements 32; These refractory elements are cut away at the bottom to form an air inlet 33 at the bottom of the thimble. This air inlet supplies air to the combustion zone of the hot water heater. Thus air flows through the short pipeSl around the thimble'channel 32 and out the air inlet 33 at the'bottom of the thimble. The air thus admitted. mixes with th combustible gases and passes up through the hollow interior of the thimble where the gases areburned in the combustion'zone'.

The refractory elements 32 which serve to parare holes 3? at the bottom of the firebox but with in the space betweenjthe side members and the sides of the firebox. These holes are in communication with the under-grate air supply that enters the heater through air hole 21 in the ash removal door 26.

The refractor thimble 28 is divided into two equal and opposite sections 28a (Fig. 4) by a plane of division passing through the apex of the thimble. Such a construction makes it easy to insert and remove the thimble.

It is preferred that the refractory thimble 28 be positioned at the top of the firebox so that the space between the bottom of the thimble and the bottom of the firebox is considerably greater than the space between the bottom of the thimble and the top of the firebox. This provides a slow burning rate as the depth of coke is large in relation to the depth of uncoked coal. The top of the coke will be substantially even with the bottom of the refractory thimble. In a typical heater there is approximately as much coke as there is uncoked coal.

When the hot water heater is in operation primary air is supplied through air hole 21 in the ash removal door 25. A portion of this primary air passes up through the grates to serve as primary under-grate air, while another portion flows through air holes 31 in the bottom of the firebox up between the sides of the firebox and side metal members 35, and out through holes 36 in these side members to the coking zone. Secondary combustion air is supplied through secondary air pipe 31, where it flows around the channel 30 in the refractory thimble 2B and out the bottom of the thimble into the combustion zone l3.

The inclined fixed grate 24 is provided with slots 38 through which the ashes fall. This inclined grate also provides for passage of air and directs the coke toward the rear. These slots are arranged in parallel alignment, and extend from near the side of the firebox through the other edge of the fixed grate. As the fixed grate is made of metal and contacts the metal side of the firebox, this construction permits the inclined grate to expand and contract without exerting any force on the metal sides of the firebox. As the side of the firebox is water-jacketed, it will not expand and contract under heat. The parallel slots 38 are wider at the bottom than they are at the top, in order to permit ashes to drop through freely. The slots may be $43" wide at the top and wide at the bottom.

The hot water heater as shown is provided with a feed opening 39 at the top of the firebox. If the feed opening is made small, smoke will not leak out when it is open. In one construction where the firebox had an internal diameter of 15%" diameter, the feed door was 4 /4" at its smallest diameter. This same hot water heater had the firebox 16 high with the bottom of the refractory thimble 9" from the bottom of the firebox.

It was found that for best construction, a hot water heater of this type should be of circular cross-section, in order to equalize stresses in the metal sides. These stresses are caused by the pressure of water flowing through the water jackets, and by the heat stresses from the burning coal.

For very cheap construction and low water demand, the top passageway it could be left off,

with the stack connected directly to the firebox. In those preferred installations where the top passageway is used, this passageway may be permitted to merely rest on top of the firebox and be held there by its own weight. It is preferred,

however, that some means of fastening the two together be used.

Having described my invention in relation to a typical embodiment of same, it is to be understood that the invention is not to be limited to any of the details of description unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claim.

I claim:

A longitudinally split refractory element for use in a stove and the like wherein said stove is provided with an air supply opening to the interior thereof and an exit for burned gases at the top of the stove, said refractory element comprising a hollow body portion open at top and bottom serving as a combustion chamber when the body portion is arranged in communication at the bottom with said interior of the stove and at the top with said exit for burned gases, and said body portion having a transverse outwardly extending flange at each of the top and bottom ends thereof with the space defined by said flanges and the outer surface of said body portion serving as an air channel when said space is arranged in communication with said air supply opening and with the bottom of said combustion chamber, said body portion being of substantially triangular transverse cross-section with one side being curved convexly and the other two sides being substantially straight and of substantially the same area, and with the split being formed by a plane lying substantially along the apex of the angle formed by the two straight sides and bisecting the curved side into two substantially equal parts.

JOHN C. MILES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 543,982 Clarey Aug. 6, 1895 1,209,106 Beck Dec. 19, 1916 1,620,805 Dawson Mar. 15, 1927 2,075,433 Eisentrager Mar. 30, 1937 2,263,926 Lewis Nov. 25, 1941 2,370,644 Essen Mar. 6, 1945 2,392,121 Christensen Jan. 1, 1946 FOREIGN PATENTS Number Country Date 380,661 Germany Sept. 11, 1923 

